Module Getopt

module Getopt: sig .. end

Short keys represent -l options. Long keys represent --long options. Some options can support both formats at once, e.g., -l and --long.

For long-key options, if the handler is Hnd1, an argument has to be passed as --long=value. If the handler is HndOpt, it can be passed either as --long or --long=value. If the handler is Hnd0, it has to be passed as --long.

For short-key options, if the handler is Hnd1, an argument can be passed either as -lvalue or -l value. If the handler is HndOpt, it can be passed either as -l or -lvalue. If the handler is Hnd0, it has be passed as -l.

Short-key options with Hnd0 or HndOpt handlers can be passed in concatenated form, i.e., -abc is parsed as -a -b -c, assuming the first argument has a Hnd0 handler.

If -- is passed, all remaining arguments are considered as raw arguments.


type key = 
| KShort of char
| KLong of string
| Key of char * string
type '_ arg = 
| AInt : int arg
| AString : string arg
| ASymbol : string list -> string arg
| APair : char * 'a arg * 'b arg -> ('a * 'b) arg
| AList : char * 'a0 arg -> 'a0 list arg
type handler = 
| Hnd0 of (unit -> unit)
| HndOpt : 'a arg * ('a option -> unit) -> handler
| Hnd1 : 'a0 arg * ('a0 -> unit) -> handler
type doc = string 
type opt = key * handler * doc 
exception GetoptFailure of string
val commands : string list Stdlib.ref

commands hold the name of the currently running command, Sys.argv.(0) by default.

val parse_one : opt list -> string array -> int -> int

parse_one opts args i parses argument args.(i) using the option list opts. If the argument is not an option (or if it is option --), i is returned. Otherwise, the index of the next unparsed argument is returned. The function raises GetoptFailure if the argument is either an unrecognized option or its required value is missing. If the option list does not change depending on parsed options, parse_many might be a better choice.

val parse_many : opt list -> string array -> int -> int

parse_many opts args i parses arguments from args starting at index i, calling parse_one in turn. It returns the index of the first argument that is not an option. When GetoptFailure is raised, the function calls handle_exn to terminate the program. If the option list is static, parse_all might be a better choice.

val parse_all : ?i:int -> opt list -> (string -> unit) -> string array -> unit

parse_all ~i opts extra args parses all the arguments from args, starting from index i (1 by default), calling parse_one in turn. When GetoptFailure is raised, the function calls handle_exn to terminate the program. When an argument is not an option, it is passed to extra. If an argument is --, all the remaining arguments are passed to extra in turn.

val format : ?margin:int -> opt list -> string

format ~margin opts turns the option list opts into a string that is suitable for usage message. The first word of a description name the argument of the option (if any). Description remainders are aligned at column margin (25 by default). If an option does not support arguments, its description string should start with a space.

val handle_exn : string -> unit

handle_exn args exn terminates the program after printing the content of the GetoptFailure exception. The content of commands is used as the program name for the error message.